There are many appraoches taught in the prior art for vehicle theft detection devices. Many of these systems use some sort of transmitting system. See, for example, U.S. Pat. No. 4,012,728 to Fowler; U.S. Pat. No. 4,319,230 to Fowler, et al.; U.S. Pat. No. 3,665,312, to Jarvis; U.S. Pat. No. 4,187,497 to Howell et al; U.S. Pat. No. 3,357,020 to Slifer, Jr.; U.S. Pat. No. 4,177,466, to Reagan; and U.S. Pat. No. 3,357,020 to Slifer, Jr.; U.S. Pat. No. 4,177,466, to Reagan; and U.S. Pat. No. 4,188,614 to Habib et al. Many of these, such as Fowler, Jarvis and Howell use a mechanism for detecting the theft of the device. For example, Fowler discloses a burglar alarm system which utilizes an electric back-up circuit. When the electrical conductor of the burglar alarm system is cut, a lock-in relay is operated to close the back-up circuit and actuate a radio transmitter to transmit radio signals to a receiver that indicated that an electrical conductor of the burglar alarm has been cut. Jarvis discloses an alarm and monitoring system for a vehicle in which a transmitter is activated upon illegal entry into, or theft of, the vehicle. The transmitter sends out a coded signal which identifies the vehicle. The signal is sent out sequentially on different frequencies with a predetermined and different time interval between each transmission. The received signals are utilized to locate the vehicle by triangulation techniques. Howell et al discloses a portable vehicle alarm system having a motion sensitive switch in a transmitter for transmitting an alarm to a remote receiver. The receiver is capable of several functions, including silent alarm to police or security guards, as well as visual and audible signals at remote locations. Further, U.S. Pat. No. 1,239,602 to Johnston, shows a steering shaft with a special protective housing constructed to include sounding an alarm if the housing is disturbed, but fails to show any alarm system responsive to tampering with the starting mechanism of the vehicle. U.S. Pat. No. 4,449,605, to Read shows a system associated with starting the vehicle after partially destroying the starting mechanism, which system prevents car movement and therefore has no alarm nor suggests an alarm. Also, the Read system is actuated by starting the vehicle rather than by the removal of a portion of the starting mechanism. U.S. Pat. No. 3,629,818, to Yokohama, et al. shows a dual test alarm system for the open door of the vehicle with the steering shaft unlocked and does not disclose an alarm intrusive to the starting mechanism with the door closed. In addition, Habib et al discloses a remote alarm system for preventing of motorcycles, bikes or other similar devices from theft. The alarm system includes a housing which is positioned on a support surface for cooperative engagement with a wheel of the vehicle.
Many other techniques have also been discovered for prevention of theft. For example, see U.S. Pat. No. 3,947,693, to Eskenas. Eskenas discloses an electrical pushbutton ignition combination lock wired into the electrical circuit of the motor of the vehicle. The proper combination of buttons must be pushed to energize a relay to complete the ignition circuit. Pressing any of the other buttons simply grounds the circuit and disables the unlocking mechanism.
However, none of the above-referenced prior art discloses a system specifically adapted to respond to the removal of the lock cylinder in the steering column or steering column intrusive starting techniques, despite the fact that most thefts involving vehicles result from a removal of the lock mechanisms from the steering column or breaking into steering columns that have no special locks. In addition, most signal devices of the prior art are very complex and not easily adapted to present police procedures.
It is an object of the present invention to teach apparatus that responds to the removal of an ignition lock to cause a silent alarm, or audible if required, to respond to the event.
It is a further object of the present invention to teach apparatus for signaling the presence of a stolen vehicle to policemen in the vicinity.